Load Packages for Mapping
library(sf)
library(dplyr)
library(ggplot2)
library(leaflet)
library(scales)
library(ggmap)
Read in Map Data
ak_regions<-read_sf("shapefiles/ak_regions_simp.shp")
class(ak_regions)
## [1] "sf" "tbl_df" "tbl" "data.frame"
head(ak_regions)
## Simple feature collection with 6 features and 3 fields
## geometry type: MULTIPOLYGON
## dimension: XY
## bbox: xmin: -179.2296 ymin: 51.15702 xmax: 179.8567 ymax: 71.43957
## CRS: 4326
## # A tibble: 6 x 4
## region_id region mgmt_area geometry
## <int> <chr> <dbl> <MULTIPOLYGON [°]>
## 1 1 Aleutian I… 3 (((-171.1345 52.44974, -171.1686 52.41744, -1…
## 2 2 Arctic 4 (((-139.9552 68.70597, -139.9893 68.70516, -1…
## 3 3 Bristol Bay 3 (((-159.8745 58.62778, -159.8654 58.61376, -1…
## 4 4 Chignik 3 (((-155.8282 55.84638, -155.8049 55.86557, -1…
## 5 5 Copper Riv… 2 (((-143.8874 59.93931, -143.9165 59.94034, -1…
## 6 6 Kodiak 3 (((-151.9997 58.83077, -152.0358 58.82714, -1…
st_crs(ak_regions) #Provides projection information
## Coordinate Reference System:
## User input: 4326
## wkt:
## GEOGCS["GCS_WGS_1984",
## DATUM["WGS_1984",
## SPHEROID["WGS_84",6378137,298.257223563]],
## PRIMEM["Greenwich",0],
## UNIT["Degree",0.017453292519943295],
## AUTHORITY["EPSG","4326"]]
Plotting Data
plot(ak_regions)
#Doesn't look correct, need to transform
Read in Population Data
pop <- read.csv("shapefiles/alaska_population.csv")
pop_4326<-st_as_sf(pop,
coords=c("lng","lat"),
crs= 4326, #set this here according to what the data are
#currently in, not what you want them to be in
remove=FALSE)
#head(pop_4326)
#Cannot join pop with ak until they have the same coordinate system
pop_3338<-pop_4326 %>%
st_transform(crs=3338)
pop_joined <- st_join(pop_3338, ak_regions_3338, join = st_within)
plot(pop_joined)
pop_region<-pop_joined %>%
as.data.frame() %>%
group_by(region) %>%
summarise(total_pop=sum(population))
pop_region_3338<-left_join(ak_regions_3338,pop_region,by="region")
plot(pop_region_3338)
pop_mgmt_338 <- pop_region_3338 %>%
group_by(mgmt_area) %>%
summarize(total_pop = sum(total_pop),do_union=FALSE) #do_union=FALSE maintains the regions delineated
## `summarise()` ungrouping output (override with `.groups` argument)
plot(pop_mgmt_338)
rivers_3338 <- read_sf("shapefiles/ak_rivers_simp.shp")
st_crs(rivers_3338)
## Coordinate Reference System:
## No user input
## wkt:
## PROJCS["Albers",
## GEOGCS["GCS_GRS 1980(IUGG, 1980)",
## DATUM["unknown",
## SPHEROID["GRS80",6378137,298.257222101]],
## PRIMEM["Greenwich",0],
## UNIT["Degree",0.017453292519943295]],
## PROJECTION["Albers_Conic_Equal_Area"],
## PARAMETER["standard_parallel_1",55],
## PARAMETER["standard_parallel_2",65],
## PARAMETER["latitude_of_center",50],
## PARAMETER["longitude_of_center",-154],
## PARAMETER["false_easting",0],
## PARAMETER["false_northing",0],
## UNIT["Meter",1]]
MAPS!
ggplot()+
geom_sf(data=pop_region_3338, mapping = aes(fill = total_pop)) +
geom_sf(data = rivers_3338, aes(size = StrOrder), color = "black") +
geom_sf(data=pop_3338,mapping=aes(),size=0.5)+
scale_size(range=c(0.01,0.2),guide=FALSE)+
theme_bw() +
labs(fill = "Total Population") +
scale_fill_continuous(low = "gray90", high = "purple", labels = comma)
Basemaps
pop_3857 <- pop_3338 %>%
st_transform(crs = 3857)
# Define a function to fix the bbox to be in EPSG:3857
# See https://github.com/dkahle/ggmap/issues/160#issuecomment-397055208
ggmap_bbox_to_3857 <- function(map) {
if (!inherits(map, "ggmap")) stop("map must be a ggmap object")
# Extract the bounding box (in lat/lon) from the ggmap to a numeric vector,
# and set the names to what sf::st_bbox expects:
map_bbox <- setNames(unlist(attr(map, "bb")),
c("ymin", "xmin", "ymax", "xmax"))
# Coonvert the bbox to an sf polygon, transform it to 3857,
# and convert back to a bbox (convoluted, but it works)
bbox_3857 <- st_bbox(st_transform(st_as_sfc(st_bbox(map_bbox, crs = 4326)), 3857))
# Overwrite the bbox of the ggmap object with the transformed coordinates
attr(map, "bb")$ll.lat <- bbox_3857["ymin"]
attr(map, "bb")$ll.lon <- bbox_3857["xmin"]
attr(map, "bb")$ur.lat <- bbox_3857["ymax"]
attr(map, "bb")$ur.lon <- bbox_3857["xmax"]
map
}
bbox <- c(-170, 52, -130, 64) # This is roughly southern Alaska
ak_map <- get_stamenmap(bbox, zoom = 4)
ak_map_3857 <- ggmap_bbox_to_3857(ak_map)
ggmap(ak_map_3857) +
geom_sf(data = pop_3857, aes(color = population), inherit.aes = F) +
scale_color_continuous(low = "gray90", high = "purple", labels = comma)
## Coordinate system already present. Adding new coordinate system, which will replace the existing one.
Leaflet Practice!
epsg3338 <- leaflet::leafletCRS(
crsClass = "L.Proj.CRS",
code = "EPSG:3338",
proj4def = "+proj=aea +lat_1=55 +lat_2=65 +lat_0=50 +lon_0=-154 +x_0=0 +y_0=0 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs",
resolutions = 2^(16:7))
pop_region_4326 <- pop_region_3338 %>% st_transform(crs = 4326)
m <- leaflet(options = leafletOptions(crs = epsg3338)) %>%
addPolygons(data = pop_region_4326,
fillColor = "gray",
weight = 1)
pal <- colorNumeric(palette = "Reds", domain = pop_region_4326$total_pop)
m <- leaflet(options = leafletOptions(crs = epsg3338)) %>%
addPolygons(data = pop_region_4326,
fillColor = ~pal(total_pop),
weight = 1,
color = "black",
fillOpacity = 1,
label = ~region) %>%
addLegend(position = "bottomleft",
pal = pal,
values = range(pop_region_4326$total_pop),
title = "Total Population")
m
